Pen



FIG. 1 is a front elevational view of a pen showing my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a top plan view thereof; and

FIG. 6 is a bottom plan view thereof.

The clip has been omitted from FIGS. 5 and 6 for convenience ofillustration.

The ornamental design for a pen, substantially as shown.